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(No Mod l.)

V. A. COOK. EXTENSION TRANSMITTER FOR TELEPHONES.

Patented May 24, 1892.

l l l UNITED STATES PATENT OFFICE.

VICTOR A. COOK, OF NEW YORK, N. Y.

EXTENSION-TRANSMITTER FOR TELEPHONES.

SPECIFICATION forming part of Letters Patent N0. 47 5,300, dated May 24,1892.

Application filed January 8, 1892.

To all whom it may concern.-

Be it known that I, VICTOR A. 000K, of New York, in the county and Stateof New York, have invented a new and useful Improvement in ExtensionTransmitters for Telephones; and I do hereby declare that thefollowingis a full and exact description thereof, reference being had tothe accompanying drawings, and to the letters of reference markedthereon, making a part of this specification.

The object of my invention is to produce an improved extension-mouthpiece for telephone-transmitters, which, while properly directing thesound-waves from the mouth to the diaphragm, shall effectually guardagainst the transmission of metallic vibration, and thereby overcome adifficulty which has existed hitherto in the use ofextension-mouthpieces, and accomplish other desirable results, ashereinafter set forth.

A further objecl is to adapt the extension for convenient use by personsof different heights.

In the drawings, Figure l is a perspective view of my improved extensionready for application to the transmitter. Fig. 2 is a central sectionthereof, and Fig. 3 is an end elevation of the tube.

A tube A, of convenient length and diameter and having a usualmouthpiece B, is bent, substantially as shown, with a double bend. Thetube should be cast of some suitable metal, preferably brass, not merelyto enable any desired degree of curvature to be given to it, but mainlybecause the objectionable metallic twang is much less noticeable than intubes otherwise formed. Its inner end is made to fit within a sleeve 0,which projects from the clip D, the fit being sufficiently snug to holdthe tube in place, while permitting it to be rotated, as indicated bydotted lines in Fig.2. A disk E, preferably rounded in cross-section andprovided with holes 6 e, is supported by arms 6' 6 within the innerendof the tube and is of such diameter at its base as to leave an annularspace between itself and the tube. On the inner side of the clip D is aconical flange F, which enters the aperture in the door or casing G infront of the diaphragm H. The

Serial No. 417,408. (No model.)

clip is made of spring metal and is formed with hooked ends K, by whichit maybe conveniently secured to the box of the transmitter.

I have found that by bending the tube of the extension the sound-wavesdue to the vibration of the metal are broken up and not transmitted, asusual, to the diaphragm, and an indirect course is given to thesoundwaves caused by the voice,which largely prevents injurious shocksupon the diaphragm, while the sound-waves caused by the voice are alsotoned down somewhat, with good results in the distinctness of the soundsreceived at the other end of the line. Furthermore, the particular shapegiven to the tube enables the mouthpiece to be adjusted to suit theconvenience of the person using the transmitter. The perforated disk inthe end of the tube further breaks the sound-waves and distributes themevenly over the diaphragm, guardingit from shocks. The flange on theinner side of the clip prevents the escape of the sound-waves and, beingconical, focuses them properly upon the diaphragm.

I claim as my invention 1. An extension-mouthpiece fortelephonetransmitters, consisting of a tube, a disk of smaller diametersupported centrally within the tube, a spring-plate for securing thetube in front of the transmitter, and a conical flange supported by theclip and adapted to enter the aperture in the casing over thetransmitter,substantially as shown and described.

2. An extension-1nouthpiece for telephonetransmitters, consisting of atube having a double bend, substantially as shown, a disk of smallerdiameter, arms attached to the tube and disk and supporting the lattercentrally within the former, and a supportingplate having a sleeve toreceive the end of the tube and wherein the tube is rotatable,substantially as shown and described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

VICTOR A. COOK.

Witnesses:

A. N. J ESBERA, A. WIDDER.

